Studies on lead exposure in patients of a neighborhood health center: Part I. Pediatric patients.

A sharply focused study is presented defining the demographic characteristics of the catchment area of a St Louis health center and determining the blood lead (PbB) levels in children from 1977 to 1989. The sources of lead exposure are examined, and the adequacy of erythroprotoporphyrin (EP) determinations are evaluated to identify children with toxic levels. Mean PbB levels and prevalence rates at higher ranges were not only substantially higher in the catchment area population than in white children, but also significantly higher than in black children nationally. Since 1980, mean PbB declined progressively in the catchment area children, but it was not until 1989 that the mean PbB had declined to the 1980 level in white children nationally. PbB parameters in the catchment area children were not only higher than in children in other St Louis neighborhoods, but also higher than in children living in towns adjacent to a lead smelting operation. The environmental sources of lead considered here do not appear to fully account for the higher PbB levels in the children in the catchment area. Nutritional factors also need to be considered. Furthermore, the EP lacks both sensitivity and specificity for identifying children with PbB levels greater than or equal to 25 micrograms/dL and greater than or equal to 15 micrograms/dL. While this study identifies a community that has experiences a high prevalence of lead toxicity in its children, it also suggests that nationwide and even citywide estimates of the prevalence of lead toxicity based on EP screening may be significantly lower than actual prevalences.